1. Field of the Invention
The present disclosure relates to a cyclone separator for separating a mixture containing solid particles, liquid and/or gas into a heavy fraction and a light fraction.
2. Description of the Related Art
Separating devices for separating such mixtures, such as mixtures of oil and gas, are known in which use is made of the differences in specific weight of the parts of which the mixture is made up. A cyclone separator generally consists of a tube in which a central flow body is arranged. Provided on the flow body are guide fins with which the mixture flowing into the tube under overpressure is brought into rotation. As a result of the centrifugal forces occurring due to the rotation, the relatively heavy fraction of the mixture is flung outward, while the relatively light fraction of the mixture is displaced in a zone along the flow body. Because the light and heavy fractions are displaced in separate zones, a separation of the mixture can be effected by arranging outlet provisions at a suitable location, and the separated light and heavy fractions can be discharged separately.
Cyclone separators are used in a large number of situations. Inlet cyclones are, for instance, applied in gravity separation vessels. Inlet cyclones ensure that the incoming mixture undergoes a determined pretreatment before a further separation takes place. The inlet cyclone is connected for this purpose to the inlet of the gravity separation vessel and is provided with an outlet for the heavy fraction and an outlet for the light fraction, wherein both outlets debouch in the interior of the gravity separation vessel for further separation of the mixture. An example of an inlet cyclone is described in the European patent application EP 1 187 667 A2.
Another type of cyclone separator is the so-called in-line separator in which the incoming mixture and at least a part of the outgoing mixture flows through a pipeline, wherein the separator is essentially aligned with the pipeline. In-line cyclone separators can be subdivided into two different types.
In a first type, also known as a “degasser,” the separator separates gas from liquid. The degasser is used, in the case of the gas/liquid mixture, when the continuous phase is liquid. An example of a degasser is known from WO 01/00296 A1. In the degasser, the liquid continuous flow is set into rotation by a number of guide blades causing swirling. Because of the difference in density between the gas and liquid and the initiated centrifugal field, the gas is urged to the middle of the separator, thus producing a stable core of gas. Removal of the gas core is brought about by means of a gas discharge pipe arranged in the middle of the cyclone and provided with outlet openings. Because of the geometry of the separator, removal of the gas via the outlet openings takes place in radial direction.
A second type of in-line cyclone separator is a separator, also referred to as a “deliquidiser,” in which a gas continuous feed is set into rotation by a number of guide blades causing swirling. The deliquidiser in this case separates the liquid from the gas. The liquid is urged in the direction of the pipe wall, which results in a stable liquid film (layer) which is displaced in the direction of the gas outlet. In the outlet zone, the gas and the liquid are separated at a fixed position in the flow. The gas outlet is a cylindrical open pipe which is fixed in the flow space of the separator. The gas is discharged in longitudinal direction. An example of a deliquidiser is described in WO 02/056999 A1.
A drawback of the known cyclone separators is that they are relatively bulky, since provisions must be made in the separator for separate discharge of the separated heavy fraction and the separated light fraction. These provisions are usually made downstream of the guide fins, which entails a relatively large minimum length of such cyclone separators.
The present invention is directed to various devices solving, or at least reducing the effects of, some or all of the aforementioned problems.